You bring up a very good point about UC not being confined to just IM and VoIP, and the need for a more coherent definition. The way I usually think of it is to use a paradigm that places the PC (and probably eventually a mobile device) as the driving force for functionality that used to reside on separate devices. Furthermore, a single application that enables not only IM and VoIP, but video, email, unified messaging, and intuitive voice and video conferencing seems to be the direction most people are heading. That being said, I think Roar hints at a trend that seems to be the dominant force at the moment, and that is enterprises taking a staged approach to UC. For reasons pertaining to budget, infrastructure, and uncertainty, many companies are choosing to implement many features usually associated with UC one step at a time. So, for instance, a company may choose to utilize a VoIP or IM solution, but may still rely on hosted conferencing services, instead of making a big investment in an on-premise, unified solution. I would imagine that this will continue given the current economic climate.